Were they screams? Or shouts, sobs? Imagine someone in so much unremitting terror that you can hear her cries as far as the human voice can carry. For an hour after hour, without let-up.

At the time we were also getting my 100-year-old father ready for the seaside: a friend was waiting with his van out in the street. I commandeered our son Ben, pushing the wheelchair. You get used to this: we're all now capable of telling each other to drop everything instantly. Hold her safe, Ben; she’s bashing her head against the wall and I’m not strong enough to stop her.

But we’ve also become wary. We’ve all had our lives put on hold so often, for so long, to so little effect, that we've learnt to ignore the latest crisis. The last time one of my family told me Bink was suicidal I said, “Don’t tell me. Call an ambulance.” I haven’t got the expertise to stop her. Even if I still had the energy.

The sickening wails continued to swamp us in unrelenting waves.

“My daughter has a severe illness,” I explained to the workmen outside our house. “She’s having a panic attic.” Is it a panic attack? I’ve no idea. I don’t care. I just need a label to explain it with.

“We did hear something,” they admitted. It must have sounded like the threat of murder. If I heard a noise like that, wouldn’t I call the Police? Which has also happened to us, of course.

The night before, Bink had asked if there was anything she could say, any argument she could advance, any amount of money she could offer us, to be allowed not to vacate her bedroom by the weekend. We were all going to the seaside – Bink included, in theory – and had let out our house. Of course we could have reneged on the agreement. It would have been very expensive, but what is money compared to our daughter’s sanity? (We've lost enough by now, after all: when she first got ill my income dropped by over half, and never recovered.)

The point is, what good would it do? She would just transfer her terror to something else. For several years we watched a friend who was caring for her give in to her every demand, completely in thrall... till he went nuts himself and she came home: mute, ravaged, insane. After he’d had her arrested and held in a cell overnight – though he was the one who was violent. It was the most toxic relationship I’ve ever witnessed.

So we would have known from experience, even if we couldn’t have sussed it for ourselves, that giving in to her demons doesn’t work.

But standing firm to them is nerve-racking. A couple of hours later she walked through the kitchen where I still sat, stunned; where her father, her sister and I had stayed calmly listening to the howls for half the morning, not backing down.

“I’m suicidal by the way. Not that anyone here gives a shit.”

That was when I lost my bottle. People do kill themselves after threatening to: it is a myth that it’s one or the other.

The scary, lonely, really frightening thing is that there is nowhere to turn. There never has been. If my daughter had type one diabetes and was having a sugar crash, or asthma and couldn’t breathe, I would ring NHS Direct and ask them how to save her life.

Mental illness? Nothing. No help, ever. Presumably because no one knows any of the answers anyway.

I rang a psychiatrist’s secretary and got her voicemail. Please, please tell me what to do, I was almost sobbing.

That evening, we went to London for a very old friend’s party. We had postponed our much-needed holiday by half a week for it, and I had told myself over and over that no disasters falling about our ears, no behaviour of Bink's, would make me miss those three days for nothing.

At 8 o'clock Bink rang her brother Alexander at the party, and he handed his telephone to me.

“I’ve done it!” She had swum the Channel and achieved a First and received notification of her name in the New Year’s Honours. “I’m packed. I’m ready to go!” Triumph. Joy. Achievement.

“Are you pleased?”

“Yes, of course! I’m sorry I was so horrible.”

On this occasion, just this once, we seem to have made the right call. She didn’t kill herself and she is coming to the seaside.

Some time later Serena, her older sister, told me the morning wiped her out for two days. A shame, as she'd come home for a break, having a very demanding one-year-old and an extremely exhausting home-renovation project. (She also vowed that never again will she let her baby witness his aunt banging her head against a wall. She doesn’t want him to get so used to it he doesn't burst into tears in horror.)

But it does help explain why, after two decades of this, I feel older than my father.